I installed Guest Additions on my Ubuntu 10.04 VM running out of VirtualBox in order to enable directory sharing, following these instructions. Set the shared folder in the VirtualBox GUI and it mounted it on the VM, where it appeared fine.

However, when I tried going into the shared directory on the VM (located in /media), I could not cd into it nor change ownership or permissions, the commands returning without an error but not actually having done their job: